General Communication Networks Research Articles

Semi-Global Bipartite Fault-Tolerant Containment Control for Heterogeneous Multiagent Systems With Antagonistic Communication Networks and Input Saturation.

Semi-global bipartite fault-tolerant containment control framework on antagonistic communication networks is proposed in this article for heterogeneous multiagent systems (MASs) under the influence of input saturation and actuator faults. An observer is constructed to estimate the leaders' states on signed digraph, where the communication networks are antagonistic. A fully distributed virtual control approach is developed to acquire the containment trajectory. Based on the observer, a semi-global containment control method is developed to compensate for the detrimental impacts of both input saturation and actuator faults. Besides, the dynamics and state-space dimensions of the agents can be different. The proposed framework overcomes two drawbacks of the conventional containment control: 1) the containment trajectory is obtained under general antagonistic communication networks, which is more general in engineering applications and 2) both actuator faults and input saturation are solved for heterogeneous agents, which relaxes the limitation of homogeneous dynamics. Finally, a simulation example is conducted to test and verify the feasibility of the proposed method framework.

Robust cooperative output regulation for heterogeneous nonlinear multi-agent systems with an unknown exosystem subject to jointly connected switching networks

This paper investigates the robust cooperative output regulation problem for heterogeneous lower triangular nonlinear multi-agent systems with an unknown exosystem over jointly connected switching networks. The problem has been studied for the exactly known exosystem over switching networks. However, the existing result for the unknown exosystem is still limited to the static networks. To ensure that all followers acquire the reference trajectory generated by the unknown exosystem through the jointly connected switching networks, by combining a set of auxiliary filtering variables and fixed-time stability theory, an adaptive distributed observer is designed. On the basis of the adaptive distributed observer and the distributed internal model approach, we propose a distributed controller under several standard assumptions to solve the problem. Compared with the similar work subject to the static networks, the controller in this paper is applicable to the more general communication network while weakening the assumptions of the controlled system.

Distributed algorithm for economic dispatch with transmission losses under digraph

By taking transmission losses and directed communication into considered, a more practical scenario of economic dispatch problem is studied in the paper. It is formulated as a non-convex optimization problem. Using convex relaxation, the non-convex optimization problem is transformed into convex optimization problem, and the conditions to ensure that they have the same solution are given. Then, a consensus-based distributed algorithm with time-varying feedback gains is presented, which can be used to the general directed communication networks. Especially, the convergence and optimality of the proposed algorithm are proved by using multi-parameter eigenvalue perturbation theory and graph theory. Finally, simulation results validate the theoretical results and illustrate the effectiveness and advantages of the proposed algorithm.

Security in Wireless Communication Networks

Over the last decade, wireless networks have experienced significant growth due to the proliferation of mobile devices and new development of radio technologies. Since the very beginning, security for wireless communication networks has always been regarded as a critical issue. In recent research frenzy on 5G and V2X communications, security plays a pivotal role as wireless Internet access serves as critical infrastructures to facilitate the digital transcations. This book timely provides a comprehensive introduction to the security in wireless communication networks, with respect to not only general concepts, but also practical principles and cases in specific wireless communication systems. This book covers a wide range starting from the general wireless communication network architecture and basic concepts of network security to the mathematical background and practical techniques, and further to the specific security issues in different wireless networks, such as WLAN, LTE, 5G, etc. Comprehensively covering the security issues, security mechanisms, design principles, and techniques in wireless communication networks. The book intends to be a self-contained and one semester textbook on wireless security for either undergraduate senior level or graduate level courses. This book can also serve as a reference for practitioners and researchers in the field to get an idea of the current and future research focus in the emerging wireless security area.

Coding Techniques for Backscatter Communications—A Contemporary Survey

Backscatter communication (BackCom) networks enable passive/battery-free Internet-of-Thing devices, providing reliable, massive connectivity while ensuring self-sustainability, low maintenance, and low costs. Effective channel codes and decoding algorithms are necessary to achieve these objectives. However, a comprehensive survey/review paper on such techniques for BackCom networks has not been available. This paper aims to fill this gap. Because tags have limited computational resources, traditional coding techniques may not suit them. We first describe the basics of BackCom, channel codes and their relevant design parameters, and codes for general communication networks. We address the BackCom limitations, requirements, and channel characteristics. As conventional codes may not seamlessly move to the BackCom arena, we identify the potential BackCom coding techniques and multiple access schemes. We further highlight potential approaches for addressing code implementation complexity and reliability. Finally, we discuss open issues, challenges, and potential future research directions.

On the Connectivity Properties of Feasible Regions of Optimal Decentralized Control Problems

The optimal decentralized control (ODC) is an NP-hard problem with many applications in real-world systems. There is a recent trend of using local search algorithms for solving optimal control problems. However, the effectiveness of these methods depends on the connectivity property of the feasible region of the underlying optimization problem. In this article, for ODC problems with static controllers, we develop a novel criterion for certifying the connectivity of the feasible region in the case where the input and output matrices of the system dynamics are identity matrices. This criterion can be checked via an efficient algorithm, and it is used to prove that the number of communication networks leading to connected feasible regions is greater than a square root of the exponential number of possible communication networks (named patterns). For ODC problems with dynamic controllers, we prove that under certain mild conditions, the closure of the feasible region is always connected after some parameterization, for general communication networks and system dynamics.

Регіональний розвиток мережі мобільного зв’язку Київстар у Західній Україні

The mobile network (also called cellular network) is an important part of the general communication network of society, which provides interaction both between individuals and entire human communities. Mobile phones do our live easier and more convenient but the general public has only the most general ideas about the functioning of mobile communication networks. There are three most important things for mobile phone users in today's world: coverage, speed and affordability. In our article we will focus on the first component - mobile network coverage. The aim of the study is to determine the spatial features of the Kyivstar mobile network in Western Ukraine, and the main task is to analyze, based on open data, the coverage of the Kyivstar mobile network in the territorial units of Western Ukraine. The source base of the research is the data of the Kyivstar mobile communications operator. The analysis of mobile communication networks in our study was carried out on the following indicators: the area of the territory that covered by the network (mobile network area); the share of the territory that covered by the network (network coverage share). Kyivstar is the largest mobile operator in Western Ukraine both by the number of subscribers and by the area of 4G network. The Kyivstar 3G network covers only areas with a high population concentration. The Kyivstar 4G network coverage is spread over 69.9% of Western Ukraine and is absent only in the Ukrainian Carpathians and in the forest areas in the north-west of the study area. The highest rates of Kyivstar 4G network distribution are typical for the biggest cities. The northern part of Western Ukraine has the highest Kyivstar mobile coverage, and the Ukrainian Carpathians the lowest.

An intelligent transportation system for forecasting wireless communication network issues with cyber attacks

This paper propose a method to design an “Intelligent Transportation System” for forecasting wireless communication network issues with cyber attacks. Wireless communication networks(WCN) is a broadly classified and critical gateway for any communication devices because the wireless communication networks is operated at various frequency ranges in different locations. In order to maintain its performance and also to prevent any attacks due to its high data handling, we need an Intelligent transportation system (ITS) to analyse and detect the cyber-attacks before going to implement it in real time transportation. In general wireless communication networks is an IEEE 802.11 standard which can be operated at physical Transfer control protocol/Internet protocol(TCP/IP) layer as well OSI model. In this paper a novel approach to design, analyse and detect cyber-attacks is proposed for wireless communication networks transport system, called Intelligent transportation system (ITS) based cyber-attack detection. Stacked firewall system is used for reducing fake attacks and detecting real time attacks in transportation system. Hence any fake attacks or real time attacks captured by the ITS will be informed to the system controller to make decision to whether it is a false-positive or real attack. ITS is the main process of the stacked firewall system which in turn take responsible to control, maintain, and prevent any cyber-attack.

Distributed Dual Coordinate Ascent in General Tree Networks and Communication Network Effect on Synchronous Machine Learning

Due to the big size of data and limited data storage volume of a single computer or a single server, data are often stored in a distributed manner. Thus, performing large-scale machine learning operations with the distributed datasets through communication networks is often required. In this paper, we study the convergence rate of the distributed dual coordinate ascent for distributed machine learning problems in a general tree-structured network. Since a tree network model can be understood as the generalization of a star network, our algorithm can be thought of as the generalization of the distributed dual coordinate ascent in a star network. We provide the convergence rate of the distributed dual coordinate ascent over a general tree network in a recursive manner and analyze the network effect on the convergence rate. Secondly, by considering network communication delays, we optimize the distributed dual coordinate ascent algorithm to maximize its convergence speed. From our analytical result, we can choose the optimal number of local iterations depending on the communication delay severity to achieve the fastest convergence speed. In numerical experiments, we consider machine learning scenarios over communication networks, where local workers cannot directly reach to a central node due to constraints in communication, and demonstrate that the usability of our distributed dual coordinate ascent algorithm in tree networks.

Robust Dynamic Event-Triggered Coordination With a Designable Minimum Interevent Time

This article revisits the classical multiagent average consensus problem for which many different event-triggered control strategies have been proposed over the last decade. Many of the earliest versions of these works conclude asymptotic stability without proving that Zeno behavior, or deadlocks, do not occur along the trajectories of the system. More recent works that resolve this issue either: propose the use of a dwell time that forces interevent times to be lower bounded away from zero but sacrifice asymptotic convergence in exchange for practical convergence (or convergence to a neighborhood); guarantee non-Zeno behaviors and asymptotic convergence but do not provide a positive minimum interevent time guarantee; or are not fully distributed. Additionally, the overwhelming majority of these works provide no form of robustness analysis on the event-triggering strategy. More specifically, if arbitrarily small disturbances can remove the non-Zeno property then the theoretically correct algorithm may not actually be implementable. Instead, this article for the first time presents a fully distributed, robust, dynamic event-triggered algorithm, for general directed communication networks, for which a desired positive minimum interevent time can be chosen by each agent in a distributed fashion. Simulations illustrate our results.

Designing fixed-time tracking consensus protocols for networked Euler-Lagrangian systems with directed graphs

In this paper, a class of disturbed networked Euler-Lagrangian systems is investigated to track a general virtual signal under a general directed communication network. Firstly, a class of fixed-time distributed observer is constructed to estimate the leader’s state. Secondly, a local anti-disturbance tracking control based on the previous distributed observer is proposed for each follower to achieve the tracking consensus in a fixed time. A simulation example is finally conducted to verify the proposed algorithm.

Stability analysis of the linear discrete teleoperation systems with stochastic sampling and data dropout

This paper addresses the stability conditions of the sampled-data teleoperation systems consisting continuous-time master, slave, operator, and environment with discrete-time controllers over general communication networks. The output signals of the slave and master robots are quantized with stochastic sampling periods which are modeled as being from a finite set. By applying an input-delay method, the probabilistic sampling system is converted into a continuous-time system including stochastic parameters in the system matrices. The main contribution of this paper is the derivation of the less conservative stability conditions for linear discrete teleoperation systems taking into account the challenges such as the stochastic sampling rate, constant time delay and the possibility of data packet dropout. The numbers of dropouts are driven by a finite state Markov chain. First, the problem of finding a lower bound on the maximum sampling period that preserves the stability is formulated. This problem is constructed as a convex optimization program in terms of linear matrix inequalities (LMI). Next, Lyapunov–Krasovskii based approaches are applied to propose sufficient conditions for stochastic and exponential stability of closed-loop sampled-data bilateral teleoperation system. The proposed criterion notifies the effect of sampling time on the stability-transparency trade-off and imposes bounds on the sampling time, control gains and the damping of robots. Neglecting this study undermines both the stability and transparency of teleoperation systems. Numerical simulation results are used to verify the proposed stability criteria and illustrate the effectiveness of the sampling architecture.

A Survey of Emerging M2M Systems: Context, Task, and Objective

Machine-to-machine (M2M) systems enable machines or devices to collect data, exchange information, and act on the environment without direct human intervention. A device in an M2M system not only collects data for its own usage but also shares the data with other devices automatically to achieve certain goals. Therefore, emerging M2M systems for civil transportation, electric power grid, medical treatment, industrial automation, etc., can be set up based on the networking of devices. In this survey paper, we first introduce the general architecture and communication networks for M2M systems. Then, we categorize emerging M2M systems according to the types of M2M context, M2M task, and M2M objective. We further survey recent solutions for M2M systems from both academia and industry with the insights of the M2M system categorization. Finally, we summarize challenges in developing M2M system solutions.

Bilateral teleoperation of multiple agents with formation control

This paper studies the formation problem for multi-slave teleoperation system over general communication networks, where multiple mobile slave agents are coupled with a single master robot. The forward and backward network transmission time delays are assumed to be asymmetric and time-varying. Due to the quantization in the network, a dynamic quantization strategy is provided to quantize the output signals of the master robot and slave agents before transmitting. Then, a novel master-slave protocol is designed to achieve the formation task under variable time delays and quantization. Additionally, the sufficient conditions for stability are presented to show that the formation protocol can stabilize the master-slave system under variable time delays and quantization. Finally, simulation are performed to show effectiveness of the main results.

New stability criteria for networked teleoperation system

The stability problem is studied for teleoperation systems over general communication networks. Compared with previous work, both quantization and time delay issues are considered. The controller used in this paper is in the form of proportional-derivative, and the output signals of master and slave systems are quantized before being transmitted. The stability criteria are presented to show that the controller can stabilize the master–slave system under quantization and variable time delay. Additionally, we propose a new quantized measurement, which can decrease the quantization error. Finally, simulations and detailed analysis are given to show the effectiveness of the main results.

A New and Secure Cryptosystem for Image Encryption and Decryption

Illegal data access has become prevalent in wireless and general communication networks. Recently, the use of chaotic signals for secure data transmission has shown significant growth in developing chaotic encryption and decryption algorithms. The application of the Brahmagupta–Bhãskara (BB) equation for encryption is reported in a very recent article. However, a number of chaos-based algorithms are proved to be insecure in the literature. It is also shown in the literature that the BB equation based algorithm can be broken by a low complexity known plaintext attack. Hence, in this paper, a new secure cryptosystem based on the BB equation and chaos is proposed for image encryption and decryption. Cryptanalysis of the proposed cryptosystem is also provided. The efficacy of the proposed cryptosystem is illustrated through implementation results on two images.

Definition of General Requirements for Graph Visualization Software

Definition of General Requirements for Graph Visualization SoftwareThis paper contains comparative analysis of some modern graph visualization packages (for example, "Graphviz", "yFiles", "Wilmascope 3D", etc) in order to outline and characterize general requirements that could be useful for development of new graph visualization software (GVS). Relations between identified requirements and necessary related components of potential GVS are being derived. To precise these requirements there were studied an additional theoretical information sources. The main goal of this research is to improve development of new GVS providing mechanism of design templates for different kinds of tasks (for example - visualization of general graphs, diagrams, routing and communication networks, etc). The result of this research is presented in tabular form. That allows identifying the set of main components of new frameworks at early stages of software development (starting with a list of desired features and transforming it into a list of necessary components). An example of using such table in DBMS MS Access environment is provided in a study of development of imaginary GVS as a part of generic air traffic control routing system. There is made conclusion about the achieved results. It is presented information about future researches in this field.

Sensor Technologies for Future Automation Systems

Sensor technologies offer new paradigms for computation, control, communication, and collaboration. In this article, we discuss the impact of sensor technologies on automation systems and issues that must be resolved before such technologies can be applied to the domain of automation systems. Over the last decade, intelligent sensors and actuators, which are connected via traditional control networks, have become increasingly important elements of automation systems. The current performance of control networks and emerging trends in general communication networks motivate a consideration of Ethernet and wireless networks as network foundations for future automation systems. Simultaneous with this transition, the automation industry needs to incorporate emerging trends in pervasive devices and new system-level properties such as adaptation, self-organization, and self-healing. The sensor-actuator network for automation described here represents a confluence of emerging trends in device technologies, communications, and system concepts with the mature domain of automation systems. We discuss four critical infrastructure issues central to sensor-actuator networks for automation: operating systems, communications mechanisms, security, and distributed services.

Xor-trees for efficient anonymous multicast and reception

We examine the problem of efficient anonymous multicast and reception in general communication networks. We present algorithms that achieve anonymous communication, are protected against traffic analysis, and require O (1) amortized communication complexity on each link and low computational comlexity. The algorithms support sender anonymity, receiver(s) anonymity, or sender-receiver anonymity.

The Design of a Networked Product by a Network of Product Designers the Design and Implementation of Services Delivered Across a Network is a New Art…

Products and services containing hardware and software that are delivered across a network are expensive to design and carry a particularly high risk when new markets are being created in a highly competitive, global marketplace. The design and implementation of such systems in a competitive industrial environment is a relatively new art that requires distinctive skills. The rate of change in the market is so high that the resulting time pressures are changing design-to-market processes in traditional industries. Our interest is in Telecommunication Network-based Services (TNSs), a term used to describe a range of different services that rely on additions to a general communication network, such as the public telephone system, to deliver added value in the form of new products. Resulting from in-depth studies we report the design of a remote meter-reading system across a network of competing and collaborating companies. We comment on the way in which design-to-market processes are changing in our collaborating company to become more like those design processes that take place over shorter time scales in agile, responsive companies in other industrial sectors.We use the results of our analysis of records and semi-structured interview data to assess different theoretical frameworks for understanding innovation in networked products designed across company boundaries. We emphasize complexity and uncertainty across an unusually broad cultural spectrum as the identifying characteristics of TNS design and suggest that an evolutionary analogy offers the most promising theoretical framework for understanding design in this field of endeavour.